1. Field of the Invention
The present invention relates to a water spouting device which generates and spouts air bubble-entrained water by plunging water through an air-liquid interface between air and temporarily stored water.
2. Description of the Related Art
There is a water spouting device hitherto proposed which spouts air bubble-entrained water by entraining air bubbles into water to be spouted (e.g., Japanese Patent Laid-Open No. 2010-167086).
For example, the water spouting device described in the above disclosure can switch between shower water spouting of spouting water in the form of a shower and straight stream water spouting of spouting a single unified water stream. This water spouting device realizes water saving by spouting air bubble-entrained water from both spouts so as to spout large water droplets even at a low water volume while maintaining the flow velocity.
The water spouting device disclosed in Japanese Patent Laid-Open No. 2010-167086 is provided with inflow ports (jet holes), through which water flows in from a water supply source, and turns air introduced through an air intake passage into foam and entrains the air into a water stream flowing in from these inflow ports. More specifically, a negative pressure is generated in an internal space as the water from the inflow ports is jetted, and the air introduced through the air intake passage due to the negative pressure is caught in the water stream flowing in from the inflow ports and turned into fine foam before being entrained into the water. This water spouting device switches by a switching mechanism so that the air bubble-entrained water with foamy air entrained in it is spouted from shower spouts as a water stream in the form of a shower or from a straight stream spout as a single unified water stream. In such a water spouting device, the shower spouts are disposed on the outer peripheral side and the straight stream spout is disposed in a central part on the inside relative to the shower spouts, and an air intake port is provided alongside the shower spouts, separately from the shower spouts and the straight stream spout.
In the conventional technology described in the above disclosure, in the case of shower water spouting, water jetted from the plurality of internal jet holes crashes against the upper end of a separation wall surface and is separated into two water streams, and the water streams are spouted as shower spouting water through two shower spouting water flow passages. As the water is jetted from the internal jet holes, a negative pressure is generated in a space between an internal jet holes forming member (member in which the internal jet holes are formed) and a branch part forming member, and outside air is introduced through the air intake passage due to this negative pressure. The introduced outside air is caught in a water stream, which is formed of the water jetted from the internal jet holes and crashing against the upper end of the separation wall surface, and turned into fine foam and entrained into the water.
While adoption of such a configuration allows air bubble-entrained water to be spouted from the shower spouts formed around the straight stream spout, the number of shower spouts that can correspond to one internal jet hole is only two, and increasing this number may lead to uneven spouting of air bubble-entrained water.
In view of this, one can conceive of applying the mechanism of spouting air bubble-entrained water from the straight stream spout so as to omit the separation wall surface and dispose as many shower spouts as possible for one internal jet hole. One possible example of the specific configuration is a water spouting device including: a rotary member which has a straight stream spout, a shower spout disposed on the outer peripheral side of the straight stream spout, and an inflow port which is disposed on the circumference and through which water flows in from a water supply source, and which rotates around the center of the circumference as the rotational center; a straight stream flow passage extending from the inflow port to the straight stream spout; and a shower flow passage extending from the inflow port to the shower spout. When the water spouting device is used as a water faucet of a lavatory, for example, it is required to be compact in the radial direction as well as in the height direction. In order to meet the demand for compactness in the radial direction, it is preferable that the water spouting device is configured such that the inflow port is shared between straight stream water spouting and shower water spouting, and that rotating the rotary member causes water supplied from the inflow port to flow through either the straight stream flow passage or the shower flow passage.
If the separation wall surface as described in the above disclosure is omitted, it is necessary to sufficiently secure the distance from the inflow ports to the shower spouts so that the air bubble-entrained water formed in the shower flow passage spreads to each one of the shower spouts. However, given the demand for compactness in the height direction as described above, it is not always possible to sufficiently secure that distance. In order to spout the formed air bubble-entrained water from each one of the many shower spouts while reducing the distance from the inflow ports to the shower spouts, it is desirable to provide the inflow ports at positions above a region, where the shower spouts are formed, so as to achieve a balance. In one preferable example, the inflow ports are provided near the center of the region where the shower spouts are formed.
However, if the inflow ports are disposed at ideal positions (near the center in the radial direction of the region where the shower spouts are formed) relative to the shower spouts, the inflow ports are inevitably located at positions away from the straight stream spout. If the inflow ports are thus disposed on the outer peripheral side of the device, the distance from the inflow ports to the straight stream spout, which is provided at the center, becomes longer. This in turn causes the water flowing from the inflow ports to the straight stream spout to decrease in flow velocity before plunging through the air-liquid interface above the straight stream spout, which may result in a decrease in amount of air bubbles entrained into straight stream spouting water. It is therefore preferable to dispose the inflow ports at positions off-center on the straight stream spout side, taking into account a decrease in amount of air bubbles entrained into straight stream spouting water, while forming the inflow ports relatively on the shower spout side.
If the openings of the inflow ports are thus not provided directly above near the center of the region where the shower spouts are formed but disposed at positions on one side eccentric to the center in the radial direction of the shower spout, a difference occurs in the flow velocity of water streams depending on the position of the shower spout. More specifically, the flow velocity of a water stream spouted from a shower spout on one side is higher, while the flow velocity of a water stream spouted from a shower spout on the other side is lower. Moreover, when a difference in flow velocity occurs between shower spouting water on one side and that on the other side, a slower water stream is attached to a faster water stream and the water spouted from the shower spouts becomes a single water stream, so that no water stream in the form of a shower is formed.
The present invention has been devised in view of these problems, and an object of the present invention is to provide a water spouting device which can switch between shower water spouting and straight stream water spouting and can spout air bubble-entrained water in both water spouting states, the water spouting device capable of entraining a large amount of air bubbles in both water spouting states of shower water spouting and straight stream water spouting, as well as of spouting shower water evenly at a high flow velocity.